void main() {
  //字面量
  var nums = <int>{1,2,3};
  print(nums);

  //构造函数
  var fruits = new Set();
  fruits.add('apple');
  fruits.add('banana');
  fruits.add('orange');
  print(fruits);
  print(fruits.toList());

  List myNums = [1,2,3];
  print(myNums.toSet());

  //集合特有的操作
  var caocao = {'张飞','关羽','刘备'};
  var xiahou = {'关羽','张飞','赵云'};
  print(caocao.union(xiahou));
  print(caocao.intersection(xiahou));
  
}
